Stellar wind




This article is about gas ejected from the atmosphere of stars. For other uses, see Stellar wind (disambiguation).



This image shows the wind from the star LL Orionis generating a bow shock (the bright arc) as it collides with material in the surrounding Orion Nebula.


A stellar wind is a flow of gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric.


Different types of stars have different types of stellar winds.


Post-main-sequence stars nearing the ends of their lives often eject large quantities of mass in massive (M˙>10−3{displaystyle scriptstyle {dot {M}}>10^{-3}}scriptstyle {dot {M}}>10^{{-3}} solar masses per year), slow (v = 10 km/s) winds. These include red giants and supergiants, and asymptotic giant branch stars. These winds are understood to be driven by radiation pressure on dust condensing in the upper atmosphere of the stars.[1][2][3][4][5][6]


Massive stars of types O and B have stellar winds with lower mass loss rates (M˙<10−6{displaystyle scriptstyle {dot {M}}<10^{-6}}scriptstyle {dot {M}}<10^{{-6}} solar masses per year) but very high velocities (v > 1–2000 km/s). Such winds are driven by radiation pressure on the resonance absorption lines of heavy elements such as carbon and nitrogen.[7] These high-energy stellar winds blow stellar wind bubbles.




In planetary nebula NGC 6565, a cloud of gas was ejected from the star after strong stellar winds.[8]


G-type stars like the Earth's Sun have a wind driven by their hot, magnetized corona. The Sun's wind is called the solar wind. These winds consist mostly of high-energy electrons and protons (about 1 keV) that are able to escape the star's gravity because of the high temperature of the corona.


Stellar winds from main-sequence stars do not strongly influence the evolution of lower mass stars such as the Sun. However, for more massive stars such as O stars, the mass loss can result in a star shedding as much as 50% of its mass whilst on the main sequence: this clearly has a significant impact on the later stages of evolution. The influence can even be seen for intermediate mass stars, which will become white dwarfs at the ends of their lives rather than exploding as supernovae only because they lost enough mass in their winds.



See also




  • Cosmic ray

  • Cosmic wind



References





  1. ^ 1941-, Lamers, Henny J. G. L. M., (1999). Introduction to stellar winds. Cassinelli, Joseph P. Cambridge, U.K.: Cambridge University Press. ISBN 0521593980. OCLC 38738913..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}


  2. ^ "Dust Envelopes". Stellar Physics. Astrophysical Institute Potsdam. Retrieved 7 April 2014.


  3. ^ Mattsson, L.; Wahlin, R.; Höfner, S. (January 2010). "Dust driven mass loss from carbon stars as a function of stellar parameters". Astronomy and Astrophysics. 509: A14. doi:10.1051/0004-6361/200912084. ISSN 0004-6361.


  4. ^ Höfner, S.; Gautschy–Loidl, R.; Aringer, B.; Jørgensen, U. G. (February 2003). "Dynamic model atmospheres of AGB stars". Astronomy & Astrophysics. 399 (2): 589–601. doi:10.1051/0004-6361:20021757. ISSN 0004-6361.


  5. ^ Sandin, C.; Höfner, S. (June 2003). "Three-component modeling of C-rich AGB star winds". Astronomy & Astrophysics. 404 (3): 789–807. doi:10.1051/0004-6361:20030515. ISSN 0004-6361.


  6. ^ Sandin, C.; Höfner, S. (January 2004). "Three-component modeling of C-rich AGB star winds". Astronomy & Astrophysics. 413 (3): 789–798. doi:10.1051/0004-6361:20031530. ISSN 0004-6361.


  7. ^ Castor, J.; Abbott, D. C.; Klein, R. I. (1975). "Radiation-driven winds in Of stars". Astrophys. J. 195: 157–174. Bibcode:1975ApJ...195..157C. doi:10.1086/153315.


  8. ^ "The long goodbye". Retrieved 27 July 2015.
















-

Popular posts from this blog

Bressuire

Image
Subprefecture and commune in Nouvelle-Aquitaine, France Bressuire Subprefecture and commune Chateau de Bressuire and the Eglise Notre-Dame Coat of arms Location of Bressuire Bressuire Show map of France Bressuire Show map of Nouvelle-Aquitaine Coordinates: 46°50′27″N 0°29′14″W  /  46.8408°N 0.4872°W  / 46.8408; -0.4872 Coordinates: 46°50′27″N 0°29′14″W  /  46.8408°N 0.4872°W  / 46.8408; -0.4872 Country France Region Nouvelle-Aquitaine Department Deux-Sèvres Arrondissement Bressuire Canton Bressuire Government  • Mayor .mw-parser-output .nobold{font-weight:normal} (2014–20) Jean Michel Bernier Area 1 180.59 km 2 (69.73 sq mi) Population (2014) 2 19,300  • Density 110/km 2 (280/sq mi) Time zone UTC+01:00 (CET)  • Summer (DST) UTC+02:00 (CEST) INSEE/Postal code 79049 /79300 Elevation 98–236 m (322–774 ft) (avg. 173 m or 568 ft) 1 French Land Register data, which exclude...
Read more

Vorschmack

Image
Vorschmack Ukrainian Jewish-style vorschmack served on rye bread Course Hors d'oeuvre Region or state Eastern Europe Associated national cuisine Ashkenazi Jewish, Finnish, German, Ukrainian, Polish, Russian Main ingredients Ground meat and/or fish Cookbook: Vorschmack   Media: Vorschmack Vorschmack or forshmak (Yiddish: פֿאָרשמאַק ‎, from archaic German Vorschmack , "foretaste" [1] or "appetizer" [2] ) is an originally East European dish made of salty minced fish or meat. Different variants of this dish are especially common in Ashkenazi Jewish and Finnish cuisine. Some varieties are also known in Russian and Polish cuisine. Contents 1 In Jewish cuisine 2 In Russian cuisine 3 In Polish cuisine 4 In Finnish cuisine 5 See also 6 References In Jewish cuisine According to Gil Marks, the German name points to the possible Germanic origin of this dish. [1] William Pokhlyobkin descr...
Read more

Quarantine

Image
For other uses, see Quarantine (disambiguation). Signal flag "Lima" called the "Yellow Jack" which when flown in harbor means ship is under quarantine. A simple yellow flag (also called the "Yellow Jack") had historically been used to signal quarantine (it stands for Q among signal flags), but now indicates the opposite, as a signal of a ship free of disease that requests boarding and inspection. A quarantine is used to separate and restrict the movement of people; it is 'a restraint upon the activities or communication of persons or the transport of goods designed to prevent the spread of disease or pests', for a certain period of time. [1] This is often used in connection to disease and illness, such as those who may possibly have been exposed to a communicable disease. [2] The term is often erroneously used to mean medical isolation, which is "to separate ill persons who have a communicable disease from those who are healthy...
Read more